The present invention relates to a filtering device with an agitator. The filtering device broadly consists of a horizontal filter plate with a central discharge opening and an agitator shaft disposed vertically and centrally to the filter plate. The agitator shaft has two agitator arms, with agitator blade being disposed on the agitator arms, pointing towards the filter plate and set at an angle to their circular path.
Filtering devices of this kind, which are also known as agitator-type suction filters, are used for the following steps of the filtering process: filtering, washing (suspension), drying, and removal. The agitator is of crucial importance here. After filtering, it serves, in the washing process, to suspend the filter cake in the washing agent. In the drying state, the agitator serves to divide the washed filter cake into fine particles and to ensure that there is good heat exchange and exchange of compounds with the heated container wall, as well as to remove the solid matter as far as possible from the suction filter. Agitation of the solid filter cake causes particular problems as the said filter cake offers a high degree of resistance to the agitator.
Therefore, agitators are used which, e.g. by means of an additional movement of stroke, ensure that the agitator blades are only inserted by degrees into the filter cake. Agitators of this kind are very expensive and sealing the agitator shaft poses a particular problem.
The object of the present invention was to improve the filtering device described initially in such a way that the agitator only requires a rotating seal and that nevertheless the agitator blades only act gradually on the filter cake.